Tension management devices for stented prosthesis delivery device

ABSTRACT

Delivery devices and methods for delivering a stented prosthesis to a target site are disclosed. Disclosed delivery devices include a handle assembly including an actuator, an inner shaft assembly interconnected to the handle assembly, and are configured to releasably retain the stented prosthesis to the delivery device with at least one elongate tension member. The delivery devices further include a tension management device that is configured to limit the amount of tension that can be applied via the actuator to the at least one tension member. Certain embodiments are configured to apply different tension limits to different tension members that are controlled by a one or more actuators. Other various embodiments include one or more tension adjustors to selectively adjust one or more tension limits.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/941,158, filed on Jul. 28, 2020, which is a continuation of U.S.application Ser. No. 15/916,900, filed on Mar. 9, 2018, now U.S. Pat.No. 10,772,727, which claims the benefit of the filing date of U.S.Provisional Patent Application No. 62/469,111, filed Mar. 9, 2017, theentire teachings of which are incorporated herein by reference.

BACKGROUND

This disclosure relates to delivery devices and tension managementdevices to control and limit the tension applied to at least oneelongate tension member compressively retaining a stented prosthesis tothe delivery device.

A human heart includes four heart valves that determine the pathway ofblood flow through the heart: the mitral valve, the tricuspid valve, theaortic valve, and the pulmonary valve. The mitral and tricuspid valvesare atrio-ventricular valves, which are between the atria and theventricles, while the aortic and pulmonary valves are semilunar valves,which are in the arteries leaving the heart. Ideally, native leaflets ofa heart valve move apart from each other when the valve is in an openposition, and meet or “coapt” when the valve is in a closed position.Problems that may develop with valves include stenosis in which a valvedoes not open properly, and/or insufficiency or regurgitation in which avalve does not close properly. Stenosis and insufficiency may occurconcomitantly in the same valve. The effects of valvular dysfunctionvary, with regurgitation or backflow typically having relatively severephysiological consequences to the patient.

Diseased or otherwise deficient heart valves can be repaired or replacedusing a variety of different types of heart valve surgeries. Oneconventional technique involves an open-heart surgical approach that isconducted under general anesthesia, during which the heart is stoppedand blood flow is controlled by a heart-lung bypass machine.

More recently, minimally invasive approaches have been developed tofacilitate catheter-based implantation of the valve prosthesis on thebeating heart, intending to obviate the need for the use of classicalsternotomy and cardiopulmonary bypass. In general terms, an expandablevalve prosthesis is compressed about or within a catheter, insertedinside a body lumen of the patient, such as the femoral artery, anddelivered to a desired location in the heart where the valve prosthesisis then deployed.

The disclosure presents improvements related to the above.

SUMMARY

The present disclosure relates to delivery devices for stentedprosthesis loading, delivery and implantation. Such delivery devices caninclude an optional outer delivery sheath assembly, an inner shaftassembly and a handle assembly. The delivery devices provide a loadeddelivery state in which the stented prosthesis is loaded and compressedover the inner shaft assembly. Compression of the stented prosthesis canbe adjusted with one or more elongate tension members, e.g., sutures orthe like, which extend around the stented prosthesis and proximately toan actuation and release assembly, which can, in some embodiments, beprovided in the handle assembly. The delivery device can be manipulatedto adjust tension in the tension members to permit the stentedprosthesis to compress, self-expand, and ultimately release from theinner shaft assembly.

Disclosed embodiments further include a tension management device tomaintain the necessary tension in one or more tension members (i.e.compression of the stented prosthesis) while also preventing the overtensioning of tension members to the point of damage or failure, whichcould compromise the procedure. In various embodiments, the tensionmanagement device is configured to limit the tension that can be appliedto one or more tension members having differing predetermined tensionlimits. In further embodiments, the tension management device can adjustor toggle between varying tension limits for the one or more tensionmembers. The disclosed embodiments result in a user friendly device thatlikely increases user confidence and is believed to reduce the riskassociated with transcatheter stented prosthesis delivery proceduresutilizing elongate tension members for retaining the stented prosthesison the delivery device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example of a delivery device fordelivering a stented prosthesis.

FIG. 2A is a schematic illustration of the delivery device of FIG. 1having the stented prosthesis positioned over an inner shaft assembly ofthe delivery device in a compressed arrangement with a plurality ofelongate tension members.

FIG. 2B is a schematic illustration of the delivery device of FIG. 2Ahaving the stented prosthesis positioned over the inner shaft assemblyof the delivery device in an expanded arrangement with the plurality ofelongate tension members.

FIG. 3A is a perspective view of a stented prosthetic heart valve thatcan be used with the delivery devices disclosed herein shown in theexpanded arrangement.

FIG. 3B is a front view of the stented prosthetic heart valve of FIG. 3Ain the compressed arrangement.

FIG. 4 is a side view of one handle assembly having a tension managementdevice that can be used with a delivery device, such as that of FIGS.1-2B.

FIG. 5 is a perspective view of an actuator of the handle assembly ofFIG. 4 .

FIG. 6A is a partially exploded, first side view of a tension managementdevice incorporated into the handle assembly of FIG. 4 .

FIG. 6B is a partially exploded, second side view of the tensionmanagement device of FIG. 6A.

FIG. 6C is a partial top view of the assembled tension management deviceof FIGS. 4 and 6A-6B (a housing of the tension management device isshown as transparent for ease of illustration).

FIG. 6D is a partial side view of the assembled tension managementdevice of FIGS. 4 and 6A-6C (the housing of the tension managementdevice is shown as transparent for ease of illustration).

FIG. 7A is an enlarged view of select components of the tensionmanagement device of FIGS. 4 and 6A-6D illustrating a reel biased with abiasing element such that it engages a drive gear when tension in arespective tension member is below a predetermined limit.

FIG. 7B is an enlarged view of select components of the tensionmanagement device of FIGS. 4 and 6A-7A illustrating the reel disengagedwith the drive gear, against the bias of the biasing element, when thetension in the respective tension member exceeds the predeterminedlimit.

FIG. 8A is a partial, side view of an alternate handle assembly having atension management device including a toggle switch configured to adjustthe predetermined tension limit of at least one tension member connectedto a reel of the tension management device (a housing of the tensionmanagement device is shown as transparent for ease of illustration).

FIG. 8B is a partial, side view of the handle assembly of FIG. 8Ashowing the toggle switch in a first position (wherein the housing isshown as transparent for ease of illustration).

FIG. 8C is a partial, side view of the handle assembly of FIGS. 8A-8Bshowing the toggle switch in a second position (wherein the housing isshown as transparent for ease of illustration).

FIG. 9 is a top view of an alternate tension management device (having ahousing shown as transparent for ease of illustration).

FIG. 10 is a side view of an alternate handle assembly having a tensionmanagement device that can be used with a delivery device, such as thatof FIGS. 1-2B.

FIG. 11 is a partial, side view of an alternate actuator engaging adrive gear of the tension management device of FIG. 10 (a housing of thetension management device is shown as transparent for ease ofillustration).

DETAILED DESCRIPTION

Specific embodiments of the present disclosure are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements.

As described below, aspects of the present disclosure relate to deliverydevices utilizing one or more elongate tension members (e.g., sutures,chords, wires or filaments) to retain a stented prosthesis for deliveryto a target site. By way of background, general components of onenon-limiting example of a delivery device 10 with which some embodimentsof the present disclosure are useful are illustrated in FIGS. 1-2B. Thedelivery device 10 is arranged and configured for percutaneouslydelivering a stented prosthesis. For example, the stented prosthesis canbe a stented prosthetic heart valve 30 (schematically illustrated,hereinafter “prosthetic valve”). The delivery device 10 includes anoptional outer sheath assembly 12 having an outer sheath 14, an innershaft assembly 16 and a handle assembly 18. One or more elongate tensionmembers 20 are provided, and can be considered part of the deliverydevice 10 in some embodiments or as part of the prosthetic valve 30 inother embodiments. The delivery device 10 provides a loaded, compressedarrangement (FIG. 2A) in which the prosthetic valve 30 is loaded overand is compressively retained on a spindle 22 of the inner shaftassembly 16 by the tension members 20. As is schematically illustratedin FIGS. 2A-2B, compression of the prosthetic valve 30 is adjustable byvarying the tension in the one or more tension members 20. In thisembodiment, the outer sheath 14 is interconnected to a capsule 24 thatis selectively disposed over the compressed prosthetic valve 30 andassists in constraining the prosthetic valve 30. Once loaded, compressedand optionally sheathed by the capsule 24, the prosthetic valve 30 isdelivered to the target site. When the prosthetic valve 30 is at thetarget site, the capsule 24 is withdrawn and tension in the tensionmembers 20 is lessened or released to permit the prosthetic valve 30 toself-expand to an expanded arrangement, partially releasing andultimately fully deploying the prosthetic valve 30 from the inner shaftassembly 16 (see, FIG. 2B). Movement of the outer sheath 14 and capsule24 relative to the prosthetic valve 30 can be actuated by the handleassembly 18. The present disclosure focuses on numerous ways toincorporate a tension management device into a delivery device, such asthe delivery device 10. As will be discussed in detail below, thedisclosed tension management devices are arranged and configured tomaintain and limit the tensioning force that can be transferred to theone or more tension members 20

As referred to herein, stented prostheses and stented prosthetic heartvalves useful with the various devices and methods of the presentdisclosure may assume a wide variety of configurations, such as abioprosthetic heart valve having tissue leaflets or a synthetic heartvalve having polymeric, metallic or tissue-engineered leaflets, and canbe specifically configured for replacing valves of the human heart. Thestented prostheses and prosthetic valves of the present disclosure maybe self-expandable, balloon expandable and/or mechanically expandable orcombinations thereof. In general terms, the prosthetic valves of thepresent disclosure include a stent or stent frame having an internallumen maintaining a valve structure (tissue or synthetic), with thestent frame having a normal, expanded condition or arrangement andcollapsible to a compressed condition or arrangement for loading withinthe delivery device. For example, the stents or stent frames are supportstructures that comprise a number of struts or wire segments arrangedrelative to each other to provide a desired compressibility and strengthto the prosthetic valve. The struts or wire segments are arranged suchthat they are capable of self-transitioning from, or being forced from,a compressed or collapsed arrangement to a normal, radially expandedarrangement. The struts or wire segments can be formed from a shapememory material, such as a nickel titanium alloy (e.g., Nitinol™). Thestent frame can be laser-cut from a single piece of material, or can beassembled from a number of discrete components.

One non-limiting example of the stented prosthetic valve 30 isillustrated in detail in FIGS. 3A-3B. As a point of reference, theprosthetic valve 30 is shown in a normal or expanded arrangement in theview of FIG. 3A and a compressed arrangement in the view of FIG. 3B. Theprosthetic valve 30 includes a stent or stent frame 32 and a valvestructure 34. The stent frame 32 can assume any of the forms mentionedabove, and is generally constructed to be self-expandable from thecompressed arrangement to the normal, expanded arrangement. As discussedabove, compression of the prosthetic valve 30 can be achieved with oneor more tension members 20.

The valve structure 34 of the prosthetic valve 30 can assume a varietyof forms, and can be formed, for example, from one or more biocompatiblesynthetic materials, synthetic polymers, autograft tissue, homografttissue, xenograft tissue, or one or more other suitable materials. Insome embodiments, the valve structure 34 can be formed, for example,from bovine, porcine, equine, ovine and/or other suitable animaltissues. In some embodiments, the valve structure 34 is formed, forexample, from heart valve tissue, pericardium, and/or other suitabletissue. In some embodiments, the valve structure 34 can include or formone or more leaflets 36. For example, the valve structure 34 can be inthe form of a tri-leaflet bovine pericardium valve, a bi-leaflet valve,or another suitable valve.

In some prosthetic valve constructions, such as that of FIGS. 3A-3B, thevalve structure 34 can comprise two or three leaflets 36 that arefastened together at enlarged lateral end regions to form commissuraljoints, with the unattached edges forming coaptation edges of the valvestructure 34. The leaflets 36 can be fastened to a skirt that in turn isattached to the stent frame 32. The prosthetic valve 30 includes a firstend 40 and an opposing second end 44 of the prosthetic valve 30. Asshown, the stent frame 32 can have a lattice or cell-like structure, andoptionally forms or provides posts 46 corresponding with commissures ofthe valve structure 34 as well as features 48 (e.g., crowns, eyelets orother shapes) at the first and second ends 40, 44. If provided, theposts 46 are spaced equally around frame 32 (only one post 46 is clearlyvisible in FIG. 3A).

FIGS. 4-6D collectively illustrate components of an alternate handleassembly 118. The alternate handle assembly 118 can be incorporated intoa delivery device, such as that of FIGS. 1-2B. The handle assembly 118is configured and operates similarly to the handle assembly 18 except asexplicitly stated. The handle assembly 118 of this embodiment includesan actuator 144 positioned over and engaged with one tension managementdevice 150, which is connected to one or more tension members 120positioned around a stented prosthesis as shown in FIGS. 1-2B, forexample. The actuator 144 is configured to adjust tension in the tensionmembers 120 via the tension management device 150, while the tensionmanagement device 150 further is configured to limit the amount oftensioning force that can be applied to the tension members 120. In oneexample embodiment, the actuator 144 translates rotational force of theactuator 144 to an actuator gear 156 of the tension management device150 to selectively tension or release the tension in the tension members120. In this example embodiment, the actuator 144 includes a generallycylindrical body 146 having a threaded interior surface 148. The tensionmanagement device 150 can include a housing 152, the actuator gear 156,a drive gear 158, a reel 160 and biasing element 162 (e.g., one or morepre-compressed springs, alternate resilient element or the like). Eachof the actuator gear 156 and the drive gear 158 are positioned withinthe same plane and include a plurality of interlocking teeth 164, 166(generally referenced). In this embodiment, the teeth 164 of theactuator gear 156 are angled with respect to a rotational axis of theactuator gear 156 to match the pitch of the threaded interior surface148 of actuator 144. A few of the actuator gear teeth 164 are exposedwith respect to an opening 154 in the housing 152 to enable engagementof actuator gear teeth 164 with the interior threaded surface 148 of theactuator 144. In this way, rotation of the actuator 144 in one direction(e.g., clockwise), subsequently rotates the actuator gear 156 about itsaxis, which correspondingly rotates the drive gear 158 about its axis.In conditions where the tension member tension limit is not met, thereel 160 is engaged with the drive gear 158 such that rotation of thedrive gear 158 correspondingly rotates the reel 160. For example, one ormore tension members 120 can be secured within a channel 170 of a reel160 so that as the reel 160 rotates, the tension member(s) 120 are woundand unwound around the reel 160 to correspondingly compress and expandthe prosthetic valve (not shown) as the tension in the tension member(s)120 is varied. In embodiments where more than one elongate tensionmember is used to compresses the stented prosthesis, a plurality oftension members can individually be connected to one or more respectivereels or a plurality of tension members can be secured to one elongatetension member that is connected to a reel.

The amount of tension that can be applied to compresses the stentedprosthesis with the tension member(s) 120 (i.e. the tension limit) isdictated via the selection of the biasing element 162, which ispositioned opposite the drive gear 158, between the reel 160 and thehousing 152. The biasing element 162 biases the reel 160 in thedirection of the drive gear 158 to urge at least one tooth 172(referenced generally) of the reel 160 to engage one or more pockets 174(referenced generally) in the drive gear 158 so that rotation of thedrive gear 158 directly translates to rotation of the reel 160. As bestshown in FIG. 6A, the drive gear 158 can optionally include a generallyturbine-shaped face defining generally wedge-shaped pockets 174. Thedrive gear 158 and reel 160 interface can include, for example, fourteeth 172 symmetrically positioned around the reel 160 that canrespectively engage one of sixteen pockets 174 in the drive gear 158 toengage the reel 160. In one example embodiment, each tooth 172 has agenerally triangular cross-section. The biasing element 162 is selectedto provide a biasing force such that the reel 160 engages drive gear 158in conditions where the tension in the tension member(s) 120 is underthe predetermined limit but where the reel 160 slips and disengages thedrive gear 158 in conditions where the tension meets or exceeds thepredetermined limit due to compression of the biasing element 162. Thedisplacement, or movement in which the teeth 172 of the reel 160 slipand disengage from the pockets 174 of the drive gear 158 can be about 1mm, for example.

FIG. 7A illustrates the tension management device 150 in operatingconditions where the tension applied to the elongate tension member(s)120 is under the predetermined tension limit. In this condition, theteeth 172 of the reel 160 are engaged with pockets 174 of the drive gear158. Once the maximum tension force is achieved, as shown in FIG. 7B,the biasing element 162 sufficiently compresses such that the reel teeth172 disengage from the drive gear 158, against the bias of the biasingelement 162 so that any rotation of the drive gear 158 is nottransferred to the reel 160. In this condition, tension is maintained inthe tension member(s) 120 but no additional force is applied by rotationof the drive gear 158 (i.e. even if the actuator 144 and actuator gear156 continue to drive and rotate the drive gear 158). Therefore, whenthe biasing element 162 is disengaged from the drive gear 158, the reel160 remains stationary and does not release tension in the at least onetension member 120. In certain embodiments, an audible click is providedonce the reel 160 disengages the drive gear 158 to alert the user thatthe limit has been met. The audible click can be provided, for example,as a byproduct of the reel 160 slipping relative to the drive gear 158due to the compression loaded on to the reel 160 during the slip of thereel 160 audibly clicks as it returns to the engaged state with thedrive gear 158. In this configuration, the audible click continuesduring use as the reel 160 disengages and engages with the drive gear158. In various embodiments, the tension is preselected, via selectionof the biasing element 162, to limit the applied tension to a force ofabout 90 N to about 100 N, for example.

FIGS. 8A-8C illustrate an alternate handle assembly 118′, which issubstantially similar to the handle assembly 118 disclosed above butfurther includes an optional tension limit adjuster 180 that can beincorporated into tension management devices 150, 250, 350 disclosedherein to adjust or select the tension limit of the tension managementdevice. Tension adjuster 180 can be useful, for example, when differenttension limits are desired during stented prosthesis loading anddeployment procedures. For example, in one embodiment, tension adjuster180 can function as a toggle switch for dictating the tension limitsetting of the tension management device 150. In the illustratedembodiment, the tension adjuster 180 includes a two opposing tabs 182that a user can grip to rotate the adjuster 180 in two positions (FIGS.8B-8C). In each of the two positions, the adjuster 180 varies thecompression of the biasing element 162, thus adjusting the bias on thereel 160, which correspondingly adjusts the maximum tension that can betransferred to the at least one tension member 120 connected to therespective reel 160. It is envisioned that other similar ways of varyingthe compression of the reel 160 are possible.

FIG. 9 illustrates an alternate tension management device 250 that issubstantially similar to that of FIGS. 4 and 6A-7B. In this embodiment,the tension management device 250 includes a housing 252 (shown aspartially transparent for clarity) having a window or opening 254. Thetension management device 250 further includes an actuator gear 256having at least some teeth 264 exposed with respect to the opening 254to engage the associated actuator of the handle assembly (e.g., actuator144 of FIGS. 4-5 ). The actuator gear teeth 264 are further engaged withthe respective teeth 266 a, 266 b of two drive gears 258 a, 258 b. Aswith prior disclosed embodiments, each drive gear 258 a, 258 b isconnected to a respective reel biased toward the respective drive gear258 a, 258 b with a biasing element. In this configuration, at least twotension members 220 a, 220 b retain the stented prosthesis on thedelivery device and are controllable via a single actuator (e.g.,actuator 144). A first elongate tension member 220 a is interconnectedto a first reel and a second elongate tension member 220 b isinterconnected to a second reel. The first and second reels, as well ascorresponding biasing elements, are positioned below the respectivedrive gears 258 a, 258 b and not visible in FIG. 9 but can be configuredin the same way as the drive gear 158, reel 160 and biasing element 162of FIGS. 7A-7B. In this embodiment, the tension members 220 a, 220 b arereeled in differing directions managed by opposing reel startingpositions. Similar to the prior embodiments, during operating conditionswhere the tension applied to the tension members 220 a, 220 b is underthe predetermined limit, each reel is engaged with the drive gear 258 a,258 b via one or more respective teeth (e.g., teeth 172 of FIG. 7B).Once the maximum force is achieved, the respective reel disengages fromthe respective drive gear 258 a, 258 b such that the tension ismaintained in the respective tension member(s) 220 a, 220 b, but noadditional tensioning force is applied to the respective tensionmember(s) 220 a, 220 b even if the respective drive gear 258 a, 258 bcontinues to rotate (e.g., even if the actuator gear 256, via anactuator such as actuator 144, continues to drive one or more of thedrive gears 258 a, 258 b). In some embodiments, the predeterminedtension limit differs for the first and second reels, meaning that onereel can be engaged with the respective drive gear 258 a, 258 b when thesecond reel is not. As discussed above, the tension limit for each reelcan differ by selecting the biasing element to provide the desiredbiasing force or by use of a tension adjuster to adjust the compressionof the biasing element to provide the desired biasing force. In certainembodiments, an audible click, as described above, is provided once eachreel disengages from the respective drive gear 258 a, 258 b to alert theuser that the tension limit has been met. It is envisioned that morethan two reels can be actuated by the actuator gear 256 in alternateembodiments. It is further envisioned that the delivery device caninclude one or more reels actuated by one or more respective actuatorsand/or one or more actuator gears connected to one or more respectiveactuators.

One alternate handle assembly 318 including an alternate tensionmanagement device 350 having an alternate actuator 344 is illustrated inFIGS. 10-11 . In this embodiment, the actuator 344 includes a rotatableknob 356 fixed to a shaft 357 that extends through housing 352. Theactuator gear of prior embodiments is omitted and the shaft 357 of theactuator 344 is directly connected to a drive gear 358. Rotation of theknob 356 in either the clockwise or counterclockwise direction appliescorresponding 1:1 rotation of the shaft 357 and the drive gear 358,which subsequently rotates a corresponding reel 360, thus winding orunwinding tensioning member(s) 320 on the reel 360 to further tension orrelease tension in the tensioning member(s) 320, respectively. The reel360 is biased toward the drive gear 358 with a biasing element 362,which functions as disclosed with respect to the biasing elements ofprior embodiments. The actuator 344 can be incorporated into allembodiments disclosed herein, as desired.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A delivery device comprising: at least onetension member; a handle assembly comprising an actuator configured toadjust a tension in the at least one tension member; an inner shaftassembly interconnected to the handle assembly; and a tension managementdevice comprising a first drive gear rotatable about a first axis and afirst reel rotatable about the first axis to wind the at least onetension member around the first reel, and the first reel and the firstdrive gear are biased together into engagement in a direction of thefirst axis, wherein rotating the actuator causes the first drive gear torotatably disengage from the first real when a tension in the at leastone tension member is above a predetermined tension limit.
 2. Thedelivery device of claim 1, wherein the first reel and the first drivegear are biased into engagement with an axial face of the first reelengaging an axial face of the first drive gear and the axial faces ofthe first reel and the first drive gear are each perpendicular to thefirst axis.
 3. The delivery device of claim 1, wherein the first reelcomprises a tooth that engages the first drive gear.
 4. The deliverydevice of claim 3, wherein the tooth of the first reel is configured toengage a pocket in the first drive gear to achieved the biasedengagement of the first drive gear and the first reel.
 5. The deliverydevice of claim 1, wherein a rotation of the actuator is configured torotate an actuator gear, and a rotation of the actuator gear isconfigured to rotate the first drive gear.
 6. The delivery device ofclaim 5, wherein the actuator comprises a generally cylindrical bodycomprising a threaded inner surface engaging with teeth of the actuatorgear, wherein a rotation of the actuator is configured to rotate theactuator gear by the engagement between the threaded inner surface ofthe actuator and the teeth of the actuator gear.
 7. The delivery deviceof claim 5, wherein the actuator gear and the first drive gear arepositioned within the same plane.
 8. The delivery device of claim 1,further comprising a capsule configured to sheath a compressedprosthetic heart valve after the prosthetic heart valve is compressedonto the inner shaft assembly with the at least one tension member. 9.The delivery device of claim 1, wherein the at least one tension membercomprises a first tension member and a second tension member, and theactuator is configured to adjust a tension in the first tension memberand a tension in the second tension member.
 10. The delivery device ofclaim 9, wherein the tension management device further comprises asecond drive gear rotatable about a second axis and a second reelrotatable about the second axis, the second reel and the second drivegear are biased together into engagement in a direction of the secondaxis, the first tension member is configured to be wound around thefirst reel and the second tension member is configured to be woundaround the second reel.
 11. The delivery device of claim 10, wherein arotation of the actuator is configured to rotate an actuator gear, and arotation of the actuator gear is configured to rotate the first drivegear and the second drive gear.
 12. The delivery device of claim 11,wherein the actuator gear, the first drive gear, and the second drivegear are positioned within the same plane.
 13. The delivery device ofclaim 10, wherein a rotation of the actuator is configured to cause thefirst drive gear to rotatably disengage from the first real when atension in the first tension member is above a first predeterminedtension limit, and wherein a rotation of the actuator is furtherconfigured to cause the second drive gear to rotatably disengage fromthe second real when a tension in the second tension member is above asecond predetermined tension limit.
 14. The delivery device of claim 13,wherein the tension management device is configured to rotatablydisengage the first drive gear from the first reel independently from arotatable disengagement of the second drive gear from the second reel.15. The delivery device of claim 13, wherein the first predeterminedtension limit is different than the second predetermined tension limit.16. The delivery device of claim 1, wherein the actuator is directlyconnected to the first drive gear.
 17. The delivery device of claim 1,wherein the tension management device is configured to adjust thepredetermined tension limit.
 18. The delivery device of claim 17,wherein the tension management device further comprises a switchconfigured to adjust the predetermined tension limit.
 19. The deliverydevice of claim 18, wherein the switch is configured to adjust a biasingforce that biases the first reel and the first drive gear together.